THE STUDY OF TREES. 261 



Ash (Fraxinus excelsior'). Flowers in clusters, complete 

 or male and female separate. Both kinds or one only on 

 the same tree. Stamens reddish purple, pistil greenish 

 yellow. In the complete flowers the pistil is mature 

 before stamens. Leaves appear after flowers. Wind-polli- 

 nated. Fruit termed " keys " in bunches each with a long 



Fig. 138. The Poplar twig and 

 catkin. 



Fig. 139. The Ash with a cluster 

 of fruits. 



narrow " wing " with a slight twist. Leaves large, com- 

 pound ; leaflets four to seven pairs and one terminal, ovate, 

 lanceolate. Branches stout, twigs curved upward at tip 

 in winter. Bud scales black. Bark greyish, rough, longi- 

 tudinally fissured. 



Oak (Quercus robur}. Male and female flowers separate, 

 male flowers in detached clusters in catkins, greenish; 

 female singly on short erect stalks, flower surrounded by a 

 number of overlapping scales (bracteoles) which become 

 the " cup " of the fruit. Fruit an acorn. Leaves appear 

 along with fruit. Leaves with sinuous margins. Bark 

 rough, fissured. 



